LVAD use is increasing for both bridge and destination applications, but the need for right ventricular assist is apparent, even in patients selected to avoid this complication. These patients usually receive a temporary right ventricular assist device (RVAD) with a short-lived, external pump when the need becomes apparent, although the survival rate is superior with a pre-operatively planned biventricular implant. The difficulty is a paucity of good implantable systems for RVAD use. Existing implantable LVAD pumps adapted to this use bring with them significant compromises for right sided use. PSI has created a new design of high ?specific speed? pump well-suited to the high flow but low pressure conditions of the pulmonary circulation. The true axial flow pump would be used as an interposition implant in the pulmonary artery. The design presents minimal blockage to flow to potentiate deposition or impose parasitic load on the ventricle if the pump stops. A unique bearing creates minimum shear stresses on blood, has low residence times, and works well over a very wide speed range. PTFE copolymer blood contacting surfaces are proposed, a class of material with a record of success in the pulmonary circulation. Phase I feasibility issues include demonstrating adequate performance with low static pressure drop, low bench test hemolysis, appropriate calculated shear stress fields with no stagnation/separation zones to activate platelets and deposition, and potential for high durability. With demonstration of feasibility during phase I, phase II will proceed to implant studies to confirm performance and clot-free behavior.